The PC/SC API provides a standardized interface to Smartcard readers.
The pcsc-sharp library represents a wrapper to use either Microsoft's PC/SC implementation (WinSCard) or pcsc-lite with implementations of the Common Language Infrastructure (CLI) such as .NET Framework or Mono. The library itself is written in C#.
The MCard-sharp library is a wrapper for the MCard API of SCM Microsystems, to be used on top of pcsc-sharp. It provides access to memory smart cards, in addition to the processor smart cards supported by PC/SC.
The Smartcard Commands library provides managed helpers to create, transmit and evaluate ISO-7816-4 commands for processor smart cards via pcsc-sharp. Note that this library is under 2-clause BSD license.